Rotary vortex machine

ABSTRACT

A rotary vortex machine having a stator (1) with an internal annular space (4) accommodating vanes (9) and a rotor (6) with an external annular space (7) accommodating a bridge (10) dividing the external annular space (7) into suction and delivery volumes. The rotor (6) has a curvilinear inlet passage (11) and a curvilinear outlet passage (12) to provide a flow of a service fluid essentially in one and the same direction in the suction and delivery volumes of the external annular space (7).

FIELD OF THE INVENTION

The present invention relates to constant displacement hydraulicmachines and, more particularly, to a rotary vortex machine that can beused in the capacity of a pump, compressor or motor.

PRIOR ART

Widely known in the prior art are rotary machines used as pumps ormotors having a stator with an internal working space and inlet andoutlet ports, and a rotor capable of rotating and having a bypasspassage with inlet and outlet ports.

However, the provision of friction pairs (plates-to-stator slots andplates-to-rotor pairs) in rotary machine reduces reliability of itsdesign, its economy and specific speed.

Besides, such a design involves inevitable pulsations of service fluidin working chambers which may bring about breakdowns of the machine, allthe more so at high pressures of the operating fluid.

Also known in the prior art is a rotary machine (SU, A, 735808) used asa pump and comprising a stator with an internal annular chamber withvanes, inlet and outlet ports for service fluid, and a stage forconversion of service fluid energy mounted in the stator on the drivingshaft, said stage having the form of a rotor provided with an externalannular chamber mating with the annular chamber of the stator andforming, together with it, a working annular chamber and a bridgeaccommodated in the annular chamber of the rotor and dividing it intosuction and delivery volumes connected with the inlet and outletpassages of the stator by axial holes and bypass passages arrangedparallel with a radial plane passing through the bridge.

However, in this type of communication of the suction and deliveryvolumes of the annular chamber with the inlet and outlet passages of thestator, the operating fluid in the zone of the bridge moves in oppositedirections. The fluid flow is accompanied by high energy losses sincethe fluid flow from the stator inlet port to the suction volume of theworking annular chamber turns many times through a considerable angle,passing from the axial holes into the bypass passages and thence,through other holes, into the annular chamber of the rotor.

Similar processes also occur at the rotor outlet.

It should be also noted that such a design of holes for admission anddischarge of the operating fluid fails to shape said holes in a rationalway from the viewpoint of hydrodynamics. Besides, the delivery andsuction volumes in the rotor are spaced apart at a considerable distancebecause the axial ports are separated by a bridge arranged parallel withthe radial plane which reduces the length of the operating chamber and,consequently, diminishes the region of effective vortex (circulating)interaction between the fluid flow and the vanes which, in turn,increases the back flow of the operating fluid and decreases efficiency.

SUMMARY OF THE INVENTION

The basic object of the present invention is to provide a rotary vortexmachine wherein communication of the rotor annular chamber with theinlet and outlet passages of the stator will bring the losses of energyof the operating fluid to a minimum during admission and discharge fromthe rotor which, in turn, will increase the degree of conversion ofenergy of the service fluid in the rotary machine, increase itsefficiency and reduce its dimensions.

This object is attained in the rotary vortex machine comprising a statoraccommodating an internal annular chamber with vanes, inlet and outletpassages for the operating fluid, and a stage for converting the energyof the operating fluid installed in the stator on the driving shaft,said stage being in the form of a rotor having an external annular spacecombined with the annular space of the stator and forming, togethertherewith a working annular chamber and a bridge arranged in the annularspace of the rotor and dividing it into suction and delivery volumesconnected with the inlet and outlet passages of the stator wherein,according to the invention, the rotor is provided with curvilinear inletand outlet passages connecting the suction and delivery volumes of theannular rotor space with the inlet and outlet passages of the stator anddisposed on both sides of the bridge so that the flows of the operatingfluid pass through these curvilinear passages, essentially, in one andthe same direction, the bridge on the section of these curvilinearpassages having a variable cross section and being set at an anglerelative to the radial plane of the rotor passing through said bridge.

In this design of the rotary machine the flows of the service fluid incurvilinear inlet and outlet passages are unidirectional and turning ofthe fluid flow therein is minimum. This reduces considerably the energylosses of the service fluid.

Owing to the curvilinear shape of the passages, the flow of servicefluid therein approaches that in the working passages of turbine-drivenmachines so that energy of the fluid can be additionally converteddirectly in these passages, thereby raising the total efficiency of therotary machine. Besides, the arrangement of the bridge at an anglerelative to the radial surface of the rotor has permitted makingcurvilinear passages along said surface which has reduced substantiallythe relative area occupied by said passages in the rotor, therebyproviding for maximum utilization of the length of the annular rotorspace for converting the energy due to vortex (circulating) flow offluid. This reduces the back flow of the fluid, increases the efficiencyof the rotary machine and reduces its overall dimensions.

It is practicable for the rotary machine to be provided with at leastone additional stage for converting the energy of the service fluid,arranged so that its curvilinear inlet passage communicates with thecurvilinear outlet passage of the preceding stage, and that the stagerotors are mounted on the drive shaft with provision for axial motionand be installed on supporting end seals positioned between the statorand rotor at the side of the curvilinear inlet passage.

Such a design ensures stability of efficiency, head and operationalreliability of the rotary machine due to transmission of the axial forceacting on each rotor to the individual support of each stage.

If the annular spaces of the stator and rotor are formed in their endfaces, it is practicable that the curvilinear inlet and outlet passagesof the rotor to be of a spiral-shaped form and the outlet passage of thestator to be in the form of a volute-shaped diffuser with the windingdirection opposite that of the curvilinear passages of the rotor.

In this case the inlet passage of the stator may be arranged along therotor axis.

The spiral shape of the rotor passages and of the stator outlet passagereduces the hydraulic losses caused by the flow from one element of theflow duct to another and by turns of the flow and by ensuring losses.This leads to higher efficiency while the provision of a diffuser on theperiphery of the rotary machine and axial inlet of the service fluidreduces axial dimensions of the rotary machine.

BRIEF DESCRIPTION OF THE DRAWINGS

Now the invention will be described in detail in relation to embodimentsof a rotary pump with reference to the appended drawings wherein:

FIG. 1 is a longitudinal section through the rotary pump;

FIG. 2 is a section taken along line II--II in FIG. 1;

FIG. 3 is a cross section of the rotary pump with curvilinear passagesin the rotor;

FIG. 4 is a longitudinal section of the rotary pump with twoenergy-converting stages and supporting end seals;

FIG. 5 is a longitudinal section of the rotary pump with annular workingchambers on end faces of the rotor;

FIG. 6 is a partial cross section taken along line VI--VI in FIG. 5;

FIG. 7 is a partial longitudinal section through the rotary pump withaxial fluid inlet.

BEST DETAILED DESCRIPTION OF MODES OF CARRYING OUT THE INVENTION

A rotary machine used as, say, a fluid pump comprises a stationarycasing serving as a stator 1 (FIG. 1) with an inlet passage 2 and anoutlet passage 3 and an internal annular space 4, and a fluid energyconversion stage installed in the stator 1 on a drive shaft 5, andhaving the form of a rotor 6. The external side surface of the rotor 6has an internal annular space 7 combined with the annular space 4 of thestator and forming a working annular chamber 8 therewith. The annularspace 4 (FIG. 2) of the stator 1 accommodates stationary vanes 9 whichform a plurality of individual sections in the working chamber 8.

The annular space 7 of the rotor 6 contains a bridge 10 separating itinto a suction volume 7a and a delivery volume 7b. The suction volume 7ais in communication with the inlet passage 2 (FIG. 1) by a curvilinearinlet passage 11 while the delivery volume 7b is in communication withthe outlet passage 3 through a curvilinear outlet passage 12.

The curvilinear passages 11 and 12 (FIGS. 1, 3) are arranged on bothsides of the bridge 10 and their holes 15, 16 opening onto the oppositeend faces 13, 14 of the rotor 6 are located opposite to each other asshown in FIG. 1, or they may be offset from each other depending on theparticular field of pump utilization.

Owing to such an arrangement of the curvilinear passages 11 and 12, theflows of service fluid pass through them in one direction shown byarrows A at an angle relative to the direction of rotor rotation, and inthe opposite direction. The bridge 10 (FIGS. 1 through 7) in the zonesof the curvilinear passages 11 and 12 has a varying cross section fromS₁ to S_(n) as shown in FIG. 2 and is set at an angle α to the plane Bpassing through the bridge as shown in FIGS. 1, 6.

The disclosed rotary machine used as a pump may be of a multistageconstruction.

Such a pump is used as a submersible machine for lifting liquids fromwells in which case it also has one or more additional stages 17 (FIG.4) similar to the above-described fluid energy conversion stage. Suchstages 17 are installed so that the curvilinear inlet passage 18 in eachsubsequent stage communicates with the curvilinear outlet passage 12 ofthe preceding stage. The rotors 6 and 19 of the stages 17 are mounted onthe drive shaft 5 with provision for axial movement, i.e. they are ofthe floating type, which is ensured by the provision of slotted gaps 20between the rotors and of the circular gaps 21 between the stators androtors of the stages. Each of the rotors 6 and 19 of the stages 17 isinstalled on supporting end seals 22 located between the stator androtor at the side of the curvilinear inlet passages 11 and 18. Eachsupporting end seal 22 comprises a ring 23 made of a known antifrictionwear-resistant material and disposed in an annular groove 24 on thestator or in an insert 25 between the stators 1, and a circularprojection 26 located on the rotors 6 and 19 at the side of thecurvilinear inlet passages 11, 18 and resting on the ring 23.

The rotary pump shown in FIGS. 1, 2 functions as follows.

During rotation of the rotor 6 the service fluid flows from the inletpassage 2 into the curvilinear inlet passage 11 and is thrown by thecentrifugal force to the periphery through this passage into the workingannular chamber 8 formed by the annular space 7 of the rotor 6 and theannular space 4 of the stator 1. The trajectory of the fluid in theworking chamber 8 is of a spiral circulating nature due to the curvatureof walls of the annular spaces 4 and 7 of the stator 1 and rotor 6,respectively, and the inclination of the surfaces of the vanes 9. As theservice fluid moves in the annular space 7 of the rotor 6 it is actedupon by relatively large centrifugal forces proportional to ##EQU1##where

Q--density of the fluid,

R--radius of curvature,

V_(u) --peripheral speed component of the elementary fluid particle.Under the effect of this centrifugal force the fluid particles get intothe intervane sections where the fluid practically loses the peripheralcomponent of speed and the centrifugal force acting on each particle inthese intervane sections is insignificant. Under the effect of thedifference between the centrifugal force acting on the fluid flowingfrom the circular chamber of the rotor and on the fluid in the intervanespace of the stator, portion of the fluid is forced from the intervanesection by a new portion flowing from the annular space 7 of the rotor 6and, after repreated interaction with the vanes 9, moves into thecurvilinear passage 12 wherefrom it is delivered by centripetal forceinto the outlet passage 3.

A combination of the curvilinear surfaces of the annular spaces of therotor, stator and vanes resists efficiently back flow of the fluidwhich, acquiring additional energy as in vortex pumps and using thecentrifugal and centripetal forces of rotor rotation results in increaseof the pump head.

In this design of the rotary machine there are no structural limitationsfor shaping the curvilinear form of the inlet 11 and outlet 12 passagesin accordance with the hydrodynamics of the passages of turbine-drivenmachines wherein the energy of the service fluid can be additionallyconverted at minimum losses.

The rotary pump comprising several stages 17 as shown in FIG. 4functions as follows.

The drive shaft 5 carrying rotors 6 and 19 of the sections 17 is set inrotation. The service fluid moves in the working circular chamber 8 ofeach stage just as described hereinabove for the rotary pump illustratedin FIGS. 1-3.

After the service fluid has acquired additional energy, this fluid isdelivered under pressure through the curvilinear outlet passage 12 ofone section into the curvilinear inlet passage 18 of the subsequentstage 17 and thence, into the working annular chamber of this section.

As a result, the service fluid moves in succession through all pumpsections and develops a higher head at the outlet.

The difference of pressures in the curvilinear passages 11 and 12between the working chamber in each stage 17 and the low-pressure holeof the rotor separated from each other by the slotted gap 20 produces anaxial force acting on the rotor.

Inasmuch as the total pressure differential built up by the multistagepump is large, the load on the thrust bearing may reach an impermissiblelevel. Besides, operation of the multistage pump is influenced adverselyby stage-to-stage leaks through the gaps 20, 21. Owing to the floatingconstruction of each rotor of the stage (rotor freely moving along theshaft) in which each rotor rests on end seals 22, this eliminatesstage-to-stage leaks and reduces radically the load on the bearings.

Besides, the end seals of each stage can take the axial load acting onthe stage rotor without providing the machine with a sophisticatedassembly for resisting the axial load of the rotor, said assemblyreducing the reliability of the machine considerably, all the more sofor small diametral dimensions as, for example, in a submersible wellpump.

Thus, provision of each stage of the rotary machine with supporting endseals ensures stable parameters of efficiency, head and reliability ofthe rotary machine.

Shown in FIG. 5 is an embodiment of the pump with two working chambers27 and 28 disposed on the end face surfaces of the rotor 29 and stator30. The working chamber 27 is constituted by annular spaces 31 and 32 inthe stator 30 and rotor 29, respectively, while the working chamber 28is constituted by annular spaces 33 and 34 in the stator 30 and rotor29.

The curvilinear inlet passages 35 and curvilinear outlet passages 36 inthe rotor 29 are of a spiral shape as shown in FIG. 6 while the outletpassage 37 of the stator has the form of a volute-shaped diffuser 38with its direction of winding opposite that of the curvilinear passages35 and 36 of the rotor 29.

In the embodiment shown in FIG. 7 the inlet passage 39 for service fluidis arranged along the axis of the rotor 29, said rotor beingcantilevered on the drive shaft 5, and its curvilinear inlet passages 35communicate with passage 39 as can be seen in FIG. 7.

In this embodiment of the pump the low-pressure service fluid flowsthrough the inlet passages 2 and curvilinear inlet passages 35 into theannular working chambers 27 and 28 of the pump wherefrom it isdischarged through the curvilinear outlet passages 36 into the diffuser38 and thence to the outlet opening.

The service fluid in the working annular chambers 27 and 28 acquirescirculating motion in the above-described manner and offers effectiveresistance to the back flow of the medium (along rotor rotation).

Due to the arrangement of two opposite-disposed working chambers 27 and28 there appear symmetrical pressure curves in the rotary machine. Saidpressures act on the rotor thus eliminating the forces applied to itand, consequently, improving the working conditions of the bearings andreducing the sagging of the drive shaft which increases the reliabilityof the rotary machine. Apart from that, the existence of two identicalflows increases pump capacity or power in the absence of conditions fordevelopment of cavitation of fluid. Thus, the distinctive featuresmentioned above enhance reliability, capacity and economy of the rotarymachine.

Industrial Applicability

The disclosed rotary machine used in the capacity of a pump can beutilized in numerous branches of industry. Used as a motor it driveair-operated tools, operate in air starting systems of I.C. engines andbe used as self-contained drives of various mechanisms.

We claim:
 1. A rotary vortex machine comprising a stator (1) with aninternal annular space (4) accommodating vanes (9), an inlet passage (2)and an outlet passage (3) for a service fluid, and a fluid energyconverting stage installed in the stator (1) on a drive shaft (5) andcomprising a rotor (6) having an external annular space (7) combinedwith the annular space (4) of the stator (1) and forming, together withsaid annular space (4), a working annular chamber (8), and a bridge (10)disposed in the annular space (7) of the rotor (6) and dividing saidannular space (7) of the rotor into suction and delivery volumescommunicating with the inlet passage (2) and the outlet passage (3) ofthe stator (1), said rotor (6) having a curvilinear inlet passage (11)and a curvilinear outlet passage (12) which connect the suction anddelivery volumes of the annular space (7) of the rotor (6) with theinlet passage (2) and the outlet passage (3) of the stator (1), saidcurvilinear inlet and outlet passages being arranged on both sides ofthe bridge (10) in such a manner that the flow of the service fluidmoves through said curvilinear passages (11, 12), essentially, in oneand the same direction, the bridge (10) in the zone of said curvilinearpassages (11, 12) having a variable cross section and being positionedat an angle relative to a radial plane passing through said bridge (10).2. A rotary machine as claimed in claim 1, further comprising at leastone additional stage (17) for conversion of fluid energy installed sothat its curvilinear inlet passage (18) communicates with thecurvilinear outlet passage (12) of the preceding stage, the rotors (6and 19) of the stages being mounted on the drive shaft (5) with aprovision for axial movement and installed on supporting end seals (22)located between the stators and rotors at the side of the curvilinearinlet passages (11, 18).
 3. A rotary machine as claimed in claim 1,wherein end surfaces of said annular spaces (31 and 32) of said stator(30) and said rotor (29) are provided with a spiral-shaped curvilinearinlet passage (35) and a spiral-shaped curvilinear outlet passage (36),said outlet passage (37) of the stator (30) being in the form of avolute-shaped diffuser (38) having a winding direction opposite awinding direction of said curvilinear inlet and outlet passages (35, 36)of the rotor (29).
 4. A rotary machine as claimed in claim 1, whereinsaid inlet passage (38) of the stator (30) is arranged along an axis ofrotation of the rotor (29).
 5. A rotary machine as claimed in claim 3,wherein said inlet passage (38) of the stator (30) is arranged along anaxis of rotation of the rotor (29).